You do not need to delete the existing data in Source list (if the Vendor shown on record is still valid) - Just Add a new line with New Source and Tick the MRP Column and FIXED source column on this new record and untick from the old data.

I am having problem to understand this. Sometime when I want to maintain source list for certain material and plant, there's already data. To maintain new data I need to delete the existing data. My question is, can I simply delete those data? or I need to check whether those data is still valid or anything? Can anyone explain to me? Your help is highly deeply appreciated.